Conventionally, X-ray CT apparatuses detect X-rays, which are irradiated from an X-ray tube and passed through a subject, and reconstruct an image based on a result of the detection to obtain an X-ray tomographic image.
An X-ray tube is provided inside an annular rotator, and periphery of the annular rotator is covered with a cover. A space is formed between the outer circumferential surface of the annular rotator and the inner surface of the cover.
A cooler is provided in order to effectively exhaust the heat generated from the X-ray tube. In addition to the space, the cooler has a radiator, a vent hole, an exhaust fan, and an exhaust port, for example.
The radiator is arranged in vicinity of the X-ray tube. The vent hole which leads to the space is arranged in vicinity of the radiator. The space is provided with the exhaust port which leads to the outside air. An exhaust fan is provided between the exhaust port and the vent hole. High temperature air radiated from the radiator is passed through the vent hole and the exhaust fan causes the high temperature air to be exhausted to the outside via the exhaust port (Patent Document 1) (Japanese Unexamined Patent Application Publication No. 2009-219619).
Further, as another example of the cooler, a duct for exhausting heat is provided. The duct for exhausting heat is formed so as to extend along the outer circumference of a rotating part, ensuring a length of the duct long enough to attenuate noise energy which is generated in a component and propagated inside the duct (Patent Document 2) (Japanese Unexamined Patent Application Publication No. 2010-227382).